How can I recharge the AC myself?
W. Curtiss Priest
W. Curtiss Priest, Director, CITS
Center for Information, Technology & Society
466 Pleasant St., Melrose, MA 02176
Voice: 781-662-4044 BMS...@MIT.EDU
Fax: 781-662-6882 WWW: http://cybertrails.org
Restoring Refrigerant to the Air Conditioner
Total cost: $60-$70
Total time: 2-3 hours
Porsche Model 944, 1985/1
May 20, 2002
Preface:
If you value all of your time at more than $80 an hour, stop
here. Also, if you are not, at least, at a skilled hobbiest grade
ability to work with your hands, stop here.
With the requirement that all automobiles be equipped with
the more ozone friendly refrigerant R-134 in 1995, the average
driver of a car that uses the earlier, R-12, refrigerant is
often at the mercy of specialized AC auto shops where the
cost starts at $250 in the Boston area. It requires a
federal license to handle and use R-12.
In that it is normal for a fifteen year old car to lose
about half of its refrigerant over time, the owner has only
two options. The owner can find a shop that still does
R-12 (not many do) or, they can find a shop that will
convert the car to the refrigerant R-134A.
Unfortunately this newer refrigerant, with an earlier compressor,
condensor, evaporator, will have significantly less cooling
capacity as R-134A does not, in the same system, produce as
much cooling.
In particular, a Porsche with "black on black" (black paint with
black interior) should probably NOT be converted to R-134A as
the interior will run too warm on a hot day.
Fortunately, for now, there are other choices of refrigerants on
the market that require NO conversion, may be purchased without
a federal license, and which actually provide MORE cooling
than the original R-12.
Disclaimer:
The following proceedure involves the mixing of non-R-12 freon-like
products with R-12.
This is generally frowned upon as when a licensed AC shop works
on an AC, one of the first operations is to reclaim the exiting
R-12 (or R-134A) refrigerant. If you mix a different refrigerant,
this contaminates the R-12.
Technically, one should have an AC shop remove ALL of the R-12,
and then make a full changeover.
However, if you have no significant leak, but are simply restoring
refrigerant at the "fifteen year" point of the car, there is no
harm in mixing the refrigerants, since, for the life of the car
you will continue to use this mixture. (Perhaps, still, at the
time of "disposal" there is an issue, but, if the refrigerant
behaves with R-12 compressor oil and is R-12 friendly, I still
don't see an issue.)
One should, whatever, be diligent about placing the new
refrigerant stickers on the vehicle.
The knowledge contained here is not "fool proof." There is
no substitute for having a "feel" for working with your
hands and keeping your "wits about you" in working on an
AC. For more background, please visit this excellent site:
http://members.tripod.com/~jbabs714/autoac.htm
(Here are quite wonderful colored diagrams that show
you exactly where the low-side and high-sides of
an auto AC are, and all the components of the system.)
Also, for other auto systems explanations see:
http://members.tripod.com/~jbabs714/
Whatever, do NOT charge into the port you see next to the
site glass. That is the HIGH side !
And read the warnings on the Autofrost can such as not charging
when the compressor is hot.
Difficulty with the Porsche 944:
On, at least, the 1985/1 the Nippondenso compressor's "low-
side" inlet is about 1" from the back side of the alternator.
In that one is supposed to add refrigerant with the engine
running and the AC on, this small clearance is very pesky.
Sometimes one can use the port behind the "low pressure"
switch, instead, but, that switch appears to be located ON
the compressor in an even more inaccessible location. (The
"shraeder" valve is typically depressed by the insertion
of such a switch, and, when removed, the valve closes. Then
with an appropriate fitting, that port sometimes is used.)
Secondly.
One finds that obtaining parts such as a "right angle" for
R-12 is difficult to do.
Also, the threads for fittings vary widely. While R-12
uses a standard 1/4" SAE fitting, this fitting is not always the
same length as the fittings sold for HVAC work. (The
R-12 nipple length is slightly longer, and, using HVAC nipples may
not seat to the mating seal. Also, fittings such as an HVAC
right angle (see Adapter #2), has a smaller bore such that
it will not seat properly with seals that press on the ends
of flared nipples. Ways of sealing are discussed below.)
This article describes three alternatives to achieving a
good right angle connection to the low-side inlet on
the compressor.
About the fittings:
The nipples are much like a flared compression fitting
that are commonly used with flared brass tubing for
water connections, etc.
However, the threads are not the same and the distance
from the end of the threads to the flare on the nipple
is not the same.
There are three ways one can achieve a gas tight connection
to such a flared nipple:
1. A rubber seal can be pressed against the tapered
end of the flare
Because the area of the nipple, at the end of the
flare, is small, either a rubber tube can be
pressed with sufficient psi so that gas will not
escape, or, a medium soft plastic washer will
also conform to the surface and achieve a seal
2. In some "quick disconnects," an O-ring is used to
surround the smooth part of the side of the
nipple. This has the advantage that the fitting
need not be fully pressed down to achieve a seal
3. Then, there is the use of the 45 degree angle area
-- the flared area -- to mate with a metal tube
that has also been flared. Here, the compression
nut is also tapered to 45 degrees so that pressure
is applied along the full area of the flare
It is this kind of seal that one would do for a
permanent connection.
What is a Schraeder Valve (or Valve Core)? --
Each nipple has an internal thread, like a valve
stem for a car tire. And, like a tire stem, there
is a one way valve with a stem on top that can be
depressed to open the valve.
Then, on the mating female, there is always a
depressor -- a piece of brass or plastic right
in the center that comes about flush in height
to the end of the opening.
So, these valves are placed in flares as check valves,
permitting, for example the ability to put refrigerant
into the low-side port.
In the following discussion we will describe two different
kinds of screw on angled fittings with connections as in
Adapters #1 & #2, and the use of a quick connect fitting as in
Adapter #3.
Knowing When the AC is fully Charged and Pressures:
In talking with one R-12 expert I was told that R-12 was
quite simple to understand the pressure inside the pipe
and the temperature of the liquid (or gas).
With R-12 the temperature IS the pressure. I.e., if the
pressure of a charged unit that is running is 24 psi at
the inlet valve (cold low-side) that means the refrigerant,
here, is 24 degrees farenheit !
So, R-12 in a can, at room temperature is at 70 psi.
On the high side of the compressor, where the gas is hot,
pressures can range from 200-300 psi, i.e., 200-300 degrees
farenheit.
The product I describe is ATC Specialities' Autofrost R-12
substitute. Two 12 ounce cans and a can tapper can be
bought, mail order, for $50. I also suggest you pay an
extra $10 and have them include the Quest "Leak Finder"
which puts a small amount of red dye in the system which
lets you see where a leak is, if it is fairly rapid. (The
red dye accumulates at the point, outside of the tubing, where
the refrigerant is escaping. Some old-timers simply rely
on seeing where compressor oil has accumulated. Most shops
skip this altogether and use $15,000 highly sensitive sniffers
and they can detect a leak just by catching a few molecules
of the stuff escaping from a hole.
ATC Specialities:
http://www.refrigerantsales.com/autofrost.html
1-800-622-5008
So, the pressures one finds on the low side of the compressor
ranges from ambient temperatures when the unit is off, down
to 24-30 psi when the unit is running and fully charged.
Therefore, fittings have to be pretty good, but we are not
trying to contain enormous pressures.
Also, when charging, you'll notice the charging can gets cold
as it behaves like a refrigerator as the gas expands. If, say
you let the can get down, well below freezing -- say 10 degrees,
well that means it is at 10 psi (well, about) -- and -- if
the unit is running at 30 psi, you just won't be able to put
more gas in. So, one rule is to keep the can warm by submersing
it in warm water.
Another related subject is whether you should liquid charge
or gas charge an AC system. This varies by the type of
refrigerant, but, for Autofrost, you should liquid charge
the system which means the can should be upside down. (This
is written on the their can.)
With the original R-12, the Haynes manual says to stop charging
when bubbles in the site glass disappear. With Autofrost, the
technician says you will always see some foam, even when
fully charged.
Further, if you over-charge a system, you will raise the low-side
pressure, and thereby raise the temperature going to the
evaporator which is cooling the car. So, if nothing else, a
car with too much refrigerant will not cool well.
To avoid that, you can measure the low-side pressure either
while charging, or check it afterwards. Any of the three
described adapters can have a 1/4 "T" connected to a pressure
guage (0-100 psi). Essentially any guage used for air
compressors would do. You charge until you see the low-side
pressure drop to the 25-28 psi range. Further charging will
then start raising the pressure, a condition of overcharging.
My general sense is this. The 944 wants around 950 grams
of refrigerant which is about 2 2/3rds 12 ounce cans.
Last fall I lost cooling and I saw bubbles in the site glass.
This usually occurs at about a 50% charge. By this spring
I saw NO refrigerant and no bubbles until about half a can
was put in. I put in two cans at this point, but, I did
not know to keep them warm, so some refrigerant was lost,
perhaps 1/4 of a can total.
So, you can always put more in. (You can also let some out,
but that is an environmental no-no.) Therefore, if you've just
lost cooling and see bubbles, I'd try about 1 1/3rd cans.
If you go longer, as I did, go for 1 2/3rd cans.
One GREAT thing about the Autofrost refrigerant. While
R-134A runs 5-10 degrees warmer in the same system, Autofrost
runs 5-10 degrees colder (than R-12) in the same system.
Wonderfully frigid air is coming out. Could it be even colder?
Perhaps. Perhaps, if I think on a 100 degree day it doesn't
feel like enough, I'll put a pressure guage to it and see.
Finally: Recharging
The Haynes manual is misleading. They show the low-side
valve on the compressor. But the picture does not show
that this valve is about 1" away from the alternator. And
since you want the car running, you don't want to pull the
alternator.
One alternative on some cars is to charge into the port
where the low-side pressure switch is screwed in. But, on
this system, that switch appears to be on the back side
of the compressor -- even less accessible.
So, to recharge the car we need to remove about 1/4 inch of
aluminum from the alternator casing foot, next to a hex bolt
that holds it.
I backed out the bolt about 8 turns, then I used a 1/8"
diameter chisel tooth carbide cutter in a rotary dremel.
Aluminum is soft, and fills many cutters. This particular
one, with a diamond like pattern, clears the cut aluminum
pretty well, and about 20 minutes of grinding removes enough
aluminum. Go back with a wide spacing cut cutting ball or pear
shaped cutter to smooth the area. After a year of oxidizing
this area will look "normal."
When you do this, first, make sure there is a cap on the
inlet so chips don't go there. Then, you'll find that
you must picture where a 1 1/4" high angle adapter will
hit the aluminum. Typically, you remove metal for ten minutes
and then you place the adapter over the nipple looking
where it hits. Then you grind some more.
There is plenty of metal here, so you are not weakening
anything.
And, you only have to do this once. And, you only have
to make up a charging adapter once. Hey! At that point
you'll be able to top up the 944 like 98% of the rest
of the world already can with their other vehicles :)
***
Now, you still won't be able to get the right angle on
with the compressor belt tensioned. But, if you losen
and remove the tensioning arm for this belt, you find that
the compressor swings AWAY from the alternator, enough, so
that you can get the right angle adapter onto the inlet
port and then put the arm back on, tension it, and you
should see your adapter JUST push against the area you
just ground down. (Impatience, in the form of not cutting
enough aluminum may result in breaking off the inlet port
flare, so, use the dollar bill test, and never tighten
the belt past the point a dollar bill, placed between the
right angle and the cut aluminum does not pull through.)
***
At this point you have two choices. You can charge with
or without putting the "Leak Finder" in series with the
line.
My thinking. Nine out of ten times, if you are around the
fifteen year period and lose cooling, the cause is the very
gradual loss of refrigerant and you have no "leak."
However, one is putting in only 3/4 of an ounce of red dye
which has been time-tested to be compatible with the
compressor oil and the system. (In obtaining this product,
get only Part # 204 which says R-12 and R-22 Air Conditioning;
do not get the more commonly available version of this for
R-134A.)
So, for an extra $10, you have the precaution of being able
to find a leak, should you be the 10% case that needs to.
For example, everyone knows that the shroud/spoiler at the
front bottom of the car is being pushed in by parking curbs,
etc. When I bought my car, someone had previously used some steel
to bracket the shroud in the center. And, they placed that in
a way that pushing in on the shroud caused that bracket to
buckle up into the condenser finned area. This could have
punctured a line there. I don't think so, but, with red dye
in the system I can inspect the area in six months and see.
Footnote: The Quest Leak Finder/Dye is actually an engineering marvel.
It contains various check-valves and a large O-ring and may
be used either with charging, or separately by turning a large
plastic nut to squeeze the dye into the AC. In that the
threads are plastic it is easy to cross-thread a fitting to
it, so always eye the fitting and assure yourself that it
is parallel to the body of the unit. If you wish to see
a drawing of the valving, you can visit the U.S. Patent
Office's online drawings of this invention:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1
&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1='5070917'.WKU.&OS=PN/5070917&RS=PN/
5070917
[if this line splits, rejoin without any spaces]
And, most browsers CANNOT display the TIFF images used by the
U.S. PTO. To remedy that, get the freeware TIFF image viewer plugin:
Alternatiff-1_4_2.exe, at http://www.alternatiff.com
Note: if you also have the QuickTime plug-in, be sure to disable
QuickTime from trying to interpret TIFFs by going to your
control panel (in Windows), clicking on the "QT" icon, and changing
the TIFF default to no.
The full page images at the U.S. PTO go back to 1790 ! Any
time you find a patent number on an item, you can now pull up
it's (very high resolution) image showing a sketch of it.
***
To charge:
1. Connect tapper to can and mount right angle to inlet
port as described above: move the compressor aside,
grind the aluminum, attach the right angle, and tension
the belt -- always checking for clearance with a
dollar bill. Use one of three possible right angle
adapters discussed below
2. Only charge when the car is running, when the AC is
on full. If the AC stops because the car is too cold,
turn the heat on full, and wait for the AC to start
again
3. Always liquid charge, can down, and keep in warm water
You can change cans while everything is connected.
You close the valve. You losen the brass collar,
you connect a new can, you tighten the collar and
that will puncture the new can
4. It is easy to both open and close the tapper valve
AND view the site guage. But, as above, you can
keep charging if you see big bubbles but do not
expect to see all foam go away. And do not overcharge
(either based on suggestions above or using a low-side
pressure guage)
5. Once charged, reverse step 1, and remove the right
angle, and then refit the arm and tension the belt
once more.
================================================================
Adapter Choices
(choose one of three)
Adapter #1: Using a Quest angle adapter
Of the 3 choices to fit an adapter, this one provides the
lowest profile, but the need to silver solder may encourage
some to try one of the alternatives. However, obtaining
the part is easily (and cheaply) done by mail order.
If you purchase a Quest R-134A recharge kit, the unit comes
with a straight fitting for the low-side inlet.
On the package it says that some cars require an angled
fitting and you send a check for $3.95 to the following
address, requesting this angled fitting:
EF Products, Inc.
Dallas, TX 75234
The fitting has nipples that are fully compliant with the
car's fittings.
The piece, however, is not angled sufficiently (it was angled
as much as they could and still get a knurled screwdown
over a brass 1/4" pipe and hose pipe, male nipple.
If you are familiar with silver soldering (even tin/lead soldering
may work, but would be fragile), the fitting can be reworked
in about an hour.
Steps:
1. Take a dremel cutoff wheel and cut lengthwise on the
brass collar that squeezes the male nipple when
inside a short rubber tube. Cut on one side, then
flip it over and cut on the other. Watch for the
change in color from brass to yellow (the pipe).
While you will not be able to cut all the way to
the brass pipe inlet, that small, uncut area will
break away
With the two cuts, take two screwdrivers, place
the pipe on top of a slightly spread vise, and
wedge the two screwdrivers until the brass collar
pops off.
2. To pull the brass nipple from the hose requires, again
the use of two very broad bladed screwdrivers.
You clamp the brass tubing in the vise so that
the edge of the rubber tube is just above the
top of the vise. You then come from both sides
at the same time, rocking the screwdriver handles
down to lift the end of the rubber hose, working
it off
The pipe nipples have flat edges in the direction
you are pulling, so, you are trying to overcome
that
Once you have the pipe started moving, you can
switch to a pair of needle nosed vise grips. You
surround the brass area, beneath the rubber tube
but not so tightly that you clamp to the brass
Now you can exert a lot of pull. Also, pulling
and rocking the other end of the rubber tube
helps the flat edges work out of the tube.
3. We must also remove one other heat sensitive part --
the black collar/gasket at the knurled end of
the fitting (the gasket that will mate to your
male nipple on the AC compressor inlet).
Take needle nose pliers and unscrew the Schreader
valve depresser in the center. About five turns
will release it
Now, slip a smooth jeweler screwdriver down between
this rubber collar and the sidewall of the fitting
When you've gone down 3/8" rock the screw driver to
coax the collar up. Do this on the other side.
Do not pierce the collar. The collar is quite lightweight
so it comes out without much effort
Take a marker and color the side of this collar
that faces into the fitting.
For the next step I am not supplying a dimension. You want
to put a right angle on the brass tube such that when the
knurled collar is level with the collar/gasket (and depressor)
the right angle begins immediately to a small length of
tube from the knurled fitting. On mine, the distance from
the point the brass tube is brazed into the compression
fitting to the lower side of the right angle is about
3/16." If you make the right angle to close to the fitting,
you will not get the knurled piece back far enough to clear
the AC nipple. If you make the piece too long, you will
have to cut more of the alternator aluminum to compensate.
Also, better to first cut the brass tube at about 1/2"
from the fitting's brazed edge (which is 3/16" from the
back side of the knurled nut when it is fully extended
(down) (as if screwed tightly to the AC nipple).
To put the right angle you can either take a protractor
and scribe a line and cut with a fine hacksaw or a dremel
cutoff wheel.
I have a rotary sander (7" adhesive 60 grit round paper
spins facing a table with a guide that can be set
to angles (such as on a table saw). Setting the guide
to 45 degrees I sanded until I was at the height I
marked on the tube. The other brass tube should also
be made cut at a right angle.
If you, alternatively, carefully cut using a cutoff wheel,
etc., both pieces will have a right angle if you make
your cut at a right angle.
4. Silver soldering the right angle. If a tube is a
good press fit into another (such as copper pipe fits
into couplings) one can typically place flux on both
pieces and "sweat" the joint, where the capillary action
of the crevice sucks the solder in.
However, we are making a "butt joint" which cannot, usually
be sweated unless the surfaces are very carefully machines
AND are held together very well.
So. We will "tin" both surfaces of the brass pipe right
angled ends first. Then we will hold the joint in place,
heat both pieces at once, and add some more silver solder
to fill any gaps.
While all this can be done with a bench vise, some hand
vise grips, a bernzomatic torch, silver solder and silver
solder flux, it is useful to have a clip grip that can
be placed at any height and depth.
This "hand" comes is useful for when you place one piece
in the vise and now need to hold a mating piece at the
right angle and distance, such as to solder or braze.
To make the "hand:"
Take a coat hanger that has a heavy guage steel wire
Take a spare C clamp or tiny bench vise, etc. and
drill into the clamp and tap it out for a 10-32
screw
Take one end of the coat hanger and make a small loop
so that you can no fasten the coat hanger to the vise
with a screw and washer
On the other end of the coat hanger we will put a
small spring clip. At one flea market I got about
a dozen springed clamps that are about 2" long
Again, drill a hole through the handle end of the clamp
on one arm, and fasten a loop on the other end of
the coat hanger with a 6-32 screw, nut and washer.
Note: If you have not silver soldered before, I suggest
practising on some junk brass. A bernzomatic torch is barely
able to get pieces this size up to the red hot temperature
they need to be at for the silver solder to braze to the
surface. Also, you need to keep the area fluxed so that
the red hot brass doesn't become contaminated with oxygen
from the air. Silver solder is a remarkably strong way to
join metals at a relatively low temperature.
Further Steps:
o Flux and "tin" the two mating surfaces
o Take a needle nose vise grip (a small one) and
lightly clamp just behind the knurled nut on
the shoulder of the brass tube
I then take another vise grip and clamp that to
this vise grip. Then I clamp that second vise
grip in the bench vise. This lets you get
the piece where the soldered surface points
straight up
o Take the other piece of brass and put it in the
clip on your "hand"
o Wrestle with the steel wire, bending it about until
it wants to hold the mating piece at right angles
to the first piece, i.e., the two right angle
pieces are joined
Poke at this a few times and make sure it doesn't
want to sit anywhere but here
o Now heat both pieces, applying more heat to the
tube that goes into the vise grip as it will
lose heat faster than the piece in the "hand's"
clip
You'll see the pieces ooze together, and, maintaining
full temperature work around the sides, applying
more silver solder in any remaining voids
o Take a carbide cutter and dress the area, smoothing
small lumps of silver solder to suit yourself
5. Reassembly
o Push the brass nipple back into the rubber hose and
replace the original brass collar with a stainless
steel hose clamp for this diameter
o Put the rubber gasket/collar into the fitting, places
the magic marker colored, end in. Do not attempt
this with the depressor screwed in.
o Now, take the depressor and holding it with needle
nose pliers, push in fairly hard (there is a rib
on it that grabs to the rubber) and then screw it
back in -- it should come about level to the rubber
collar. And that collar protrudes from the brass
fitting by about 1/16"
Adapter #2: Assembled from HVAC parts
A major supplier for these parts is Johnstone Supply which
has 224 stores nationwide. (This is a wholesaler, so
you walk in knowing what you want and don't ask questions :)
They carry a line of "Access Fittings." The size is called
SAE 1/4" and the threads, flares, and valves are identical
to that used on this car (Note: some vehicles use 3/8" SAE
fittings, and these, too, are available from Johnstone. But
for this car, get, only 1/4")
The male nipple on their right angle fitting has a bore
that is SMALLER than nipples with Schraeder valves and so
that nipple may or may not be compatible with some female
fittings that depend on a narrower lip of the flare.
For example, the female supplied by ATC Specialities for
their Autofrost refrigerant should NOT be screwed directly
onto this nipple. Instead, we use a copper compression
fitting that is female - female (called a 1/4 flare
swivel nut) then go to a male nipple to 1/4 copper tubing
(called a Service Valve 1/4" OD) then a short length
of rubber refrigerant tubing and then, with a second Service
Valve go back to male (which now has a Schraeder valve and the
narrower lip).
Parts List:
Qty Item Part # Price Each
2 1/4" Service Valve B10-736 $1.94
1 1/4" Flare Swivel Nut R53-047 $2.07
1 1/4x1/4 Access 90 NS-QC-E4 $7.86
1 3" 1/4 ID braided hose $ .25
4 Stainless steel hose clamps $ .75
Before assembling we take about 1/8" off the top face of
the right angle. To do this take a small drill and
determine the depth of the hole that comes to the male
nipple. By knowing the hole depth and the bore, we can
then take a straight edge and mark where that hole ends
in the square section above the knurled nut for the other
end.
The important place to remove material is on the top of
the square section on the leading edge -- the edge that
comes into the 1" cavity when placing the fitting on
the compressor.
We leave about 1/16" of brass, so we grind the top so
that it tapers down towards the leading edge by about
1/8"
I placed a mark, then held the fitting square to the
face of a disk sander (as described in alternative #1).
Assembly is fairly easy. In that the brass tubes
on the "Service Valves" have no ribbing, I cut them
back so that 7/8" of brass remained and then used 2 hose
clamps (side-by-side) at each end of the 3" rubber hose.
So, when done we have right angle to the flare swivel,
two one service valve male, to the rubber hose, then
back onto the second service valve brass pipe which ends
with a male nipple.
You place one Schraeder valve in this final male nipple.
[Be watchful for one thing about these Service Valves.
While they are almost identical to the male nipple provided
by Quest in #1, the nipple/thread area is a 1/16" shorter
than the more gently tapered flare from Quest. When you
screw this male into the outlet of the Quest Leak Finder,
you will find the hex/wrench area of the fitting comes
right up against the face of the outside wall of the Leak
Finder with the chance that the hex hits the plastic before
the end of the nipple firmly seats inside. Either slice
off an 1/8" slab from the end of the Leak Finder, or, grind
off the hex and create two flat spots on the fine threads
next to where it was, creating another place to hold the
tube from turning when tightening.]
At this point you have something that looks like alternative
#1 except a total length of 5 3/4" instead of 4 1/2" with
the Quest fitting and tubing.
Adapter #3: Johnsen's 8323 with brass elbow
When I first began this adventure I mentioned to my neighbor
what I needed and a few days later he brought me a "quick
connect" connected to a hose and a gas tapping fitting that
was for R-134A.
I only, much later, learned that NAPA dealers carry that
quick connect.
And, I was not aware that these fittings could be 3/8" ;(
So, I fitted this right angle to the hose from ATC Specialists
only to somewhat quickly realize that a 3/8" O-ring has
a very large gap around a 1/4" male nipple!
Nevertheless, having adapted one, here is how to use this
fitting, provided you get a 1/4."
The diameter of the hose on this right angle is about 1/8"
I.D. -- about half the diameter of the ATC hose.
So, one refits this by purchasing a common hardware item,
a male-male 1/4" brass, rubber hose splice.
In retrospect, I am glad to have a screw-on right angle
as in #1 and #2. If the AC nipple were easily accessible,
well, then a quick connect might be fine. But, given the
need to move the compressor back and forth, etc., using
this adapter may be a two-person job. Fortunately, when
you retension the compressor, you'll also be holding the
quick connect in place (wedged by the alternator), so the
lack of threads may present no problem.
Steps:
1. Cut the collar off the rubber hose that connects
to the right angle as described in Adapter #1.
2. As in Adapter #2, the brass head on the right angle
needs to be machined down. So, as in #2, take
a drill, determine the depth reaching in the hole
that went to the rubber hose. Again, as in #2, have
the lead edge as rounded down as possible, leaving
1/16" of brass to the inner gas passage.
This right angle has a hex top. When finished you
see a "ski slope" on the front edge, leaving about
half the hex head on the back side.
3. The right angle has a small diameter ribbed brass
fitting that went to the hose. We are going to cut
the brass off, just before the ribbing starts. We
are then going to take our hardware 1/4 double ended
ribbed splice and cut one of its ribbed sides off, leaving
the round piece in the middle and one ribbed male.
This fitting has a small hex head on its inlet and
so this piece can be removed from the "head" of the
fitting. You will see a small O-ring that is used
inside the hole that this is removed from. Be sure
NOT to lose the O-ring.
Now, we pick a number drill such that if we drill
into the end of our hardware store brass fitting (now
cut off) we will be able to press the smaller
diameter of the fitting's pipe INTO the drilled
hole of our larger diameter fitting.
And, unlike in #1 where we butt silver solder, here,
plain radio solder will be fine. Be sure to use
a paste flux, or, better, Dunton's Nokorode
Tinner's Fluid (in a squeeze bottle, available from
most welding shops).
4. Now screw the hex piece back into the right angle head,
slip a 4" piece of refrigeration hose onto the ribbed male
and terminate it with a "Service Valve" as in #2, or
it can be mated directly to ATC Specialities hose, cutting
off its female, straight fitting, using a stainless steel
hose clamp.
The advantage to using the Service Valve is you can
connect to the Leak Finder in series with the ATC
cable and coupling.
If you make it to here, yes, I made all three of these adapters
to be able to write them up ! Did this "adventure" take too
long? I don't know. I learned a heck of a lot, and I figure
they'll be putting ACs into cars for my lifetime :)
Cone Killer
> (choose one of three)
>
Adapter #4:
Porsche part # 928-573-965-03 : A/C 90 degree fitting.
re:Technical Bulletin 9501
Regards, Doug aka Cone Killer
'84 944
"W. Curtiss Priest" <BMS...@MIT.EDU> wrote in message
news:KVNG8.1007$AJ5.5...@typhoon.ne.ipsvc.net...
>
W. Curtiss Priest
> > Adapter Choices
> > (choose one of three)
> >
>
> Adapter #4:
> Porsche part # 928-573-965-03 : A/C 90 degree fitting.
>
> re:Technical Bulletin 9501
>
> Regards, Doug aka Cone Killer
> '84 944
OK. Nice to know. Only 10 times more expensive than Adapter #1 ($3.95),
at $50.70 from the dealership. And, it still has to be reengineered
to fit the Autofrost special tapper (they are ALL different as the
reverse threads on the cans all differ :)
So it about doubles the price of the job :)
("waste time, not money")
Cone Killer
"W. Curtiss Priest" <bms...@mit.edu> wrote in message
news:7643eddd.02052...@posting.google.com...
> "Cone Killer" <NOS...@hotmail.com> wrote in message
news:<%8PG8.42681$Q93.2...@news1.west.cox.net>...
> > > Adapter Choices
> > > (choose one of three)
> > >
> >
> > Adapter #4:
> > Porsche part # 928-573-965-03 : A/C 90 degree fitting.
> >
> > re:Technical Bulletin 9501
> >
> > Regards, Doug aka Cone Killer
> > '84 944
>
>
> OK. Nice to know. Only 10 times more expensive than Adapter #1 ($3.95),
> at $50.70 from the dealership. And, it still has to be reengineered
Never mind then. ;-)
> to fit the Autofrost special tapper (they are ALL different as the
> reverse threads on the cans all differ :)
>
> So it about doubles the price of the job :)
>
> ("waste time, not money")
Regards, Doug aka Cone Killer
W. Curtiss Priest
> > OK. Nice to know. Only 10 times more expensive than Adapter #1 ($3.95),
> > at $50.70 from the dealership. And, it still has to be reengineered
> -----^^^^^^ ???
>
> Never mind then. ;-)
Ah, but Doug, you do everyone who wants a minimal amount
of reengineering a great favor to provide info on
Adapter #4 ! Thank you.
Question. Is the profile on Adapter #4 low enough to
permit the AC compressor's belt to be at full (enough) tension
without any removal of aluminum from the arm on the
alternator?
"My" Adapter #1, with the lowest profile of #1-#3, with only
1/8" I.D. brass tube coming off as low as will allow the
knurl screwdown to rise to the top of the nipple threads still
requires about 1/8" of aluminum to have to go away.
Regards,
Curtiss
--
W. Curtiss Priest, Director, CITS
Center for Information, Technology & Society
466 Pleasant St., Melrose, MA 02176
Voice: 781-662-4044 BMS...@MIT.EDU
Fax: 781-662-6882 WWW: http://Cybertrails.org
Carl Carlson
refrigerant has leaked out. Are the seals so dried out that it
doesn't make sense to try to recondition them by filling the system
and running it? Is there anything I can do besides paying gastly
amounts of money to have the system rebuild? The temperature in
Tucson is in the 90's and will soon get hot. I could use some cool!
Thanks,
Carl Carlson
Cone Killer
"W. Curtiss Priest" <bms...@mit.edu> wrote in message news:3CF0E1...@mit.edu...
> Cone Killer wrote:
> > > OK. Nice to know. Only 10 times more expensive than Adapter #1 ($3.95),
> > > at $50.70 from the dealership. And, it still has to be reengineered
> > -----^^^^^^ ???
> >
> > Never mind then. ;-)
>
> Ah, but Doug, you do everyone who wants a minimal amount
> of reengineering a great favor to provide info on
> Adapter #4 ! Thank you.
>
> Question. Is the profile on Adapter #4 low enough to
> permit the AC compressor's belt to be at full (enough) tension
> without any removal of aluminum from the arm on the
> alternator?
>
Dunno, I only know 'of' it, I don't have one.
Regards, Doug aka Cone Killer
'84 944
> "My" Adapter #1, with the lowest profile of #1-#3, with only